Sequential switch



J 30, 1959 w. c. SCHUMACHER 2,892,999

SEQUENTIAL SWITCH Filed July 2. 1954 INVENTOR. WILL/HM L. .fc/lUmMl/L'R HT TORNE Y6 United States Patent SEQUENTIAL SWITCH William C. Schumacher, New York, N.Y.

Application July 2, 1954, Serial No. 441,188

6 Claims. (Cl. 340-364) (Granted under Title 35, U8. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to improvements in rotary switches, and more particularly pertains to rotary switches for electrical circuits wherein precise discrimination between consecutive taps is a desideratum.

In numerous industrial, communications, and military applications it is advantageous to utilize electrical switching means capable of setting up consecutively in predetermined order a multiplicity of circuit combinations. In most of these applications there is an obvious group of switching functions capable of setting up all of the, desired combinations. However, it has heretofore been impractical to correlate the switching functions inorder to cause all of the combinations to occur in the chosen order, particularly when the changes must occur with great rapidity.

One approach to this problem has been the cascading of a plurality of switch elements and the coupling of consecutive elements by means of an intermittent-motion linkage similarto a Geneva stop movement, or similar to the gear arrangement in a conventional odometer, wherein each element, when returning to its original position after traversing successively all of the steps it is required to occupy, carries simultaneously the element of the next higher order a distance of one position farther. For example, if each element has ten positions, the combinations that can be formed may be expressed by numerals of the decimal notation system, as many orders or digits being involved as there are elements. With a switching system having three elements, with each element having ten positions, one thousand combinations are provided. By using an intermittent-motion coupling between elements, the combinations can be caused to occur in a sequence that can be expressed by all of the numerals from 000 to 999. The intermittent motion occurs each time one element has completed the steps from 0 through 1, 2, 3 etc. to 9 and proceeding from 9 to 0 in the same direction of rotation. That is, if the three elements occupy initially the positions 1, 8 and 9 respectively, the next motion in the increasing direction of rotation will change the 9 to 0 and the 8 to 9 simultaneously. Thereafter, nine more changes will take place successively in the right hand or units order while no change takes place in either the middle (tens) order or the left hand (hundreds) order. Thereupon, the tens and units orders now being 9, another motion in the same direction of rotation will change both nines to zero and will change the 1 to a 2.

The foregoing arrangement is satisfactory for relatively slow motion applications, such as the selection of com binations of resistances in a decade box, but the intermittent character of the motion prevents application of such means to high speed requirements. On the other hand, reducing the speed from element to element by means of gearing has hitherto had the serious limitation that transfer from one position to the next in the higher orders could not be synchronized accurately with the termination of complete cycles of the lower orders because of the practical limits of the precision of gearing and because of the practical limits to the precise formation and location of moving and stationary contacts. In the example hereinabove cited, it would be diflicult to provide the precision required to cause the hundreds element to change from 1 to 2 simultaneously with the progress of the two succeeding elements from 9 to 0.v If there were five or six elements involved, the precision required would be at an inordinate level, unattainable in any con ventional manner.

The present invention overcomes the disadvantages noted above. The rotary switching system herein disjclosed dispenses with the intermittent motions heretofore employed and hence is operable at electric motor speeds heretofore deemed inordinate. The novel combination of elements of the subject device provides precise simultaneous progress of each element to the succeeding position when the lower orders are completing their respective cycles. These ends are achieved without dependence on a high order of precision as to mechanical characteristics by providing a primary preselector synchronized with the units selector for each order except units, in conjunction with a secondary preselector for each order (except units and tens) on each antecedent selector shaft except units, all these coordinating to assure precise timing of the controlled action.

The principal object of this invention is to provide a rotary switch for electrical circuits capable of establishing selectively a multiplicity of combinations of circuits.

Another object is to provide a rotary switch that is rotatable at speeds heretofore deemed inordinate to traverse and to make and break a multiplicity of circuits in predetermined sequence.

A further object is to provide a rotary switch having a plurality of elements each adapted to establish a plurality of switch positions insuccession and to cause a progression to the next position in another element in precise synchronism with its own restoration to the starting position of its sequence.

Still another object is to provide a rotary switch of the character described that is rugged in operation and can be fabricated inexpensively and facilely.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein Fig. 1 is a diagrammatic representation of a rotary switch, showing a preferred embodiment of the invention.

Fig. 2 is a diagrammatic representation of a modified form of the invention.

In the system shown in the drawings, means for discriminating in the numerical sequence 000, 001 to 999 are provided. The elements arecoupled through a gear train having a units, a tens and a hundreds switchcarrying shaft, said shafts each being coupled by the gears of said train for rotation in 10:1 ratio to the adjacent higher stage shaft. The units shaft carries a hun-' dreds and atens order preselector and 21 units order selector; the tens shaft carries a hundreds order preselector and a tens order selector; and the hundreds shaft carries a hundreds selector. Said selectors and preselectors are coupled electrically in the manner hereinafter described for'provision of high speed rotary switching.

In the gear train illustrated, pinion 21 is carried on the units shaft 23 and rotates clockwise, as shown, driving gear 25 counterclockwise. Pinion 27, which is fixed to gear 25, thus rotates counterclockwise on the axis of gear 25 to drive gear 29 clockwise. Said gear 29 is secured on the tens shaft 31, as is pinion 33, to rotate the hu dreds shaft 35 clockwise through said pinion v32,

gear 37, pinion 39 and gear 41. (The presence or absence of intermediate stages of gearing such as 25, 27 depends on mechanical considerations of rotational direction and speed ratio, and is only incidentally related to the basic features of the device). The gear train provides a reduction in the ratio of 10:1 from one shaft to the next, so that the units shaft completes 3600 of rotation as the tens shaft completes 360, and the tens shaft completes 3600 of rotation as the hundreds shaft completes 360.

The hundreds order primary preselector 43, which is carried on shaft 23, comprises a commutator having segments 45, 47 and 49, with segment 45 being coupled by a conductor to a slip ring 51, segment 47 being coupled by a conductor to a slip ring 53, and segment 49 being coupled by a conductor to a slip ring 55. The electrical connection to the hundreds order primary preselector 43 is obtained through brush 57 of conductor 59, said brush 57 engaging said segments successively as the segments of said preselector are rotated by shaft 23.

The tens order primary preselector 61, which is carried on shaft 23, comprises a commutator having segments 63, 65 and 67, with segment 63 being coupled by a conductor to a slip ring 69, segment 65 being coupled by a conductor to a slip ring 71, and segment 67 being coupled by a conductor to a slip ring 73. The electrical connection to said tens order primary preselector 61 is obtained through brush 75 of conductor 77, said brush 75 engaging said segments successively as the segments of said preselector are rotated by shaft 23.

The units order selector 79, which is carried on shaft 23, can be rotated to desired position by a suitable setting knob. (Alternatively, an electric motor drive or a coupling to associated mechanism can be provided). While no retaining deyrice is required normally for the units stage, suitable detent action, with a spring-loaded catch, can be provided. Said selector 79 comprises a commutator having ten segments denoted in the drawing by the ordinal designations through --1, etc. to --9. Said segments are coupled successively to a slip ring 81 through brush 83 as shaft 23 rotates. The electrical connection to mid units order selector 79 is obtained through brush 85 of conductor 87, said brush 85 contacting said slip ring 81 as said slip ring is rotated by shaft 23.

A secondary preselector 89, which is carried on shaft 31, comprises a commutator having segments 91, 93 and 95, with segment 91 being coupled by a conductor to a slip ring 97, segment 93 being coupled by a conductor to a slip ring 99, and segment 95 being coupled by a conductor to a slip ring 101. Conductors 103, 105 and 107 couple, respectively, slip ring 51 and brush 109, slip ring 53 and brush 111, and slip ring 55 and brush 113, said brushes 109, 111 and 113 being arranged in spaced adjacent relation to permit any one of said brushes to break its contact with one of said segments when oriented at the gap between any two of said segments, prior to making contact with the other of said two segments.

A tens order selector 115, which is carried on shaft 31, comprises a commutator having ten segments denoted in the drawing by the ordinal designations -0- through -1-, etc. to -9-. Conductors 117, 119 and 121 couple, respectively, the slip rings 69, 71 and 73 of preselector 61 to slip rings 123, 125 and 127 of said tens order selector 115 through brushes 129, 131 and 133, respectively. In turn, said slip rings 123, 125 and 127 are coupled by conductors to brushes 135, 137 and 139, respectively, said brushes being arranged in spaced adjacent relation to permit any one of said brushes to break its contact with one of said segments when oriented at the gap between any two of said segments, prior to making contact with the other of said two segments.

A hundreds order selector 141, which is carried on shaft .35, comprises a commutator having ten segments denoted in the drawing by the ordinal designations O-- through 1 etc. to 9- Conductors 143, 145, and 147 couple, respectively, the slip rings 97, 99 and 101 of secondary preselector 89 to slip rings 149, 151 and 153 of said hundreds order selector 141 through brushes 155, 157 and 159 respectively. In turn, said slip rings 149, 151 and 153 are coupled by conductors to brushes 161, 163 and 165 respectively, said brushes being arranged in spaced adjacent relation to permit any one of said brushes to break its contact with one of said segments when oriented at the gap between any two of said segments, prior to making contact with the other of said two segments.

It is thus evident that the electrical connections 59, 77 and 87 to primary preselectors 43 and 61 and to units selector 79 are coupled by the system to the segments of selectors 141, and 79 respectively, which segments can be connected to circuits (not shown) supplying distinctive potentials, frequencies or phase relationships with respect to some reference. Thus the output voltages appearing across conductors 59, 77 and 87 can identify shaft positions of shafts 35, 31 and 23. While the above discussion employs subject invention as a selector system wherein information is fed to the segments of selectors 141, 115 and 79 with output information appearing on conductors 59, 77 and 87, said invention can be utilized as a distribution system wherein voltages are supplied to conductors 59, 77 and 87 and output voltages appear across the segments of selectors 141, 115 and 79 respectively.

In the system above described, each order except the units order is provided with a primary preselector located on the units shaft 23, and the hundreds order is provided with a secondary preselector 89 on the tens shaft 31- the requisite, with respect to any particular selector other than the units selector, is the provision of a primary preselector on the units shaft and a secondary preselector on each selector shaft between its own shaft and the units shaft. This requisite would be equally applicable to orders above the hundreds, if used. It is also apparent that each order can be made adjustable individually by providing a coupling (for example, a detent arrangement) between gears 29 and 41 and the other elements on shafts 31 and 35 respectively. Such coupling could be engaged in as many equally-spaced positions as there are contacts on the selector concerned. For the embodiment of Fig. 1, there exist ten possible positions at thirty-six degree intervals.

The switches of the subject system can be set for any desired combination from 0--, 0,, -0 (or 000) to 9- 9, 9 (or 999) and are illustrated in the drawing at the position 000. Then rotation of the units stage 79 counter-clockwise to 9 is one-tenth of a revolution, and through the gear train coupling causes one onehundredth of a counter-clockwise revolution of the tens stage 115 and one one-thousandth of a counter-clockwise revolution of the hundreds stage 141. The movements of the tens and hundreds stages are thus very small, and are not here relied upon for switching, because the primary preselectors are made to change the circuits concerned. A counter-clockwise rotation of the hundreds order and tens order primary preselectors 43 and 61 through one-tenth of a revolution causes the respective inputs to be connected to the next segment of each commutator, thence to the slip rings 55 and 73 respectively, and from there to the secondary preselector 89 or the tens order selector 115, the respective conductive paths emerging at 9-- and -9 respectively. The same kind of switching operation takes place every time a stage goes through 9 to 0, or -9- to 0, clockwise, or through --O to -9, or -0 to -9, counterclockwise.

It is to be noted that two-segment preselectors could be employed under some conditions, but the use of three segments is preferred to minimize the need for precision in manufacture while providing reliable transfer of circuits.

The primary prcselectors can be of break-beforemake or make-before-break type, as required by the nature of the circuits involved. In applications where the respective advantages of both make-before-break and breakbefore-make switching are essential but the respective disadvantages of each type must be avoided, a dual channel system can be employed: A dual channel selector and preselector can be synchronized so that one channel selects non-adjacent values and the other channel selects the intervening values. Thus either channel, by itself, can be break-before-make, and the two channels combined can be make-before-b-reak or overlapping. For example, in transferring from 9-99 to -0-4), a single channel would have to provide either an open circuit in the transition or simultaneous 9s and Os, so that each condition would represent to the data-receiving device involved an indecisive transmission. However, with dual transmission, one output will remain 9-9-9 until after the other output has reached 0-0-0, and then will open the circuit. In this way, either one value or two adjacent values are transmitted always. No indecision exists, and the output indicating a transition between the two values can be interpreted facilely. This is of particular value when the digits correspond to potentials, phases or frequencies in an information transmission system, and the appearance simultaneously of 9 and 0 on one wire cannot be tolerated.

An element of such a dual channel system is shown in Fig. 2. The units selector 79 of the singlechannel switch mechanism is divided into two selectors 79 and 79, 79 being employed to select any odd-numbered value and 79 any even-numbered value in the units order. To emphasize the correspondence of parts between the basic single-channel selector described heretofore and this dual-channel selector, Fig. 2 employs reference characters identical to those of Fig. 1 except that components of the odd selector are distinguished with a prime mark and those of the even selector with a double prime mark.

Each selector has sufficiently wide gaps between its adjacent segments to afford break-before-make action with respect to its brush 83' or 83", but the conductive segments -0", 1', etc., through --9 are sufficiently wide so that at no time are both brushes 83', 83 simultaneously out of contact with their respective commutators.

The tens order preselector 61 and any higher-order preselectors on the units shaft 23 are provided with dual brushes such as 77, 77" in lieu of the corresponding single brush shown in Fig. 1. In this case also, the gap between adjacent commutator segments should be wide enough so that an individual brush, when in the gap, is out of contact with both segments for a desirable interval, but at no time are both brushes of a pair such as 77, 77" simultaneously out of contact with the segments of the commutator. The phasing or timing of the commutators is such that all brushes corresponding to the odd selector (i.e. 83, 77, 59) are simultaneously in their respective gaps when the even selector is approximately centered on --0, and all brushes of the even selector (i.e. 83", 77", 59") are simultaneously in their respective gaps when the odd selector is approximately centered on 9'.

In the event that other considerations require that the units order have an odd number of positions, these can be distributed among three or more selectors instead of the odd and even selectors just described, the sole controlling requirement being that no two consecutive positions he on the same commutator. Presumably in the usual case the total number of positions will be allocated equally, or practically so, to the three sections.

, Reverting to the odd and even selectors, it will be seen that there is always an unambiguous selection afforded by at least one of the sets of terminals, viz. 59', 77', and 87', or 59", 77", and 87", and at times there are unambiguous selections afforded by both of them. The action with respect to either the odd set or the even set is strictly analogous to that described heretofore for the basic single selector. It will be appreciated by those versed in the data-transmission art, especially with reference to that branch that utilizes step-by-step motors, that this arrangement supplies an appropriate circuit for completely, accurately, and unambiguously specifying the transmitted value within less than one position of the units selector, without circuit interruption at any time. Thus an open circuit in the transition or the simultaneous transmission through adjaeent segments of one commutator is avoided.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. As noted above, two-segment preselectors could be employed. The primary preselectors and units stage selector can be of the snap-action type with manual control for low speed operation and for high current applications. A reversal of the moving and stationary component elements is feasible. The last stage can be variable continuously intsead of affording discrete steps. The pinion, preselector and selector on any stage can be coupled to the gear thereof by cam-and-detent means or a similar means so that a desired combination can be selected without continuous rotation of the units order selector 79 to the desired position. With such coupling, a cam-operated switch can be provided to break the circuit in lieu of relying on the commutator and brush arrangement to break the circuit. Mechanical means other than gears can be used to effect the desired speed relationships among selectors.

Further, the invention is not limited to ten-position stages, nor is it required that all of the stages have the same number of positions. Other structures will suggest themselves to those skilled in the art. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

l. A rotary switch comprising a plurality of selectors for a succession of orders, said orders including a lowest order, a highest order and at least one intermediate order, each selector comprising a plurality of switch positions defined by commutator segments and a relatively rotatable means in slidable engagement with said segments for successive electrical contact therewith, a gear train engaging said relatively rotatable means for rotation in a fixed ratio, andpreseleetor systems carried by the orders below the highest order, each system comprising a primary prcselector carried by the rotatable means of the lowest order, and a secondary preselector carried by each relatively rotatable means intermediate the rotatable means of the lowest order, and the respective order selector, each preselector consisting of a rotary switch having commutator segments, slip rings and contact members to transfer the point of contact with higher order segments in response to predetermined rotation of said rotatable means of the lowest order.

2. A switch comprising a multiplicity of selector assemblies including a first assembly, a second assembly and a third assembly, coupling means connecting said selector assemblies for progression from one to another of their respective selections at different rates; said rates bearing a predetermined relationship to each other such that as the first of said selector assemblies progresses from one to another of its selections the second of said selector assemblies accomplishes a cycle of its selections and the third of said selector assemblies accomplishes a plurality of cycles-of its selections, said first selector assembly comprising a first plurality of selection segments and a first plurality of selective means each adapted to make similar assaeaa selections from among said first plurality of selection segments at overlapping spaced intervals, two of said first plurality of selective means being adapted at times to make different selections therefrom concurrently, said second selector assembly comprising a selector and a secondary preselector, said selector comprising a second plurality of selection segments, and a second plurality of selective means each adapted to make similar selections from among said second plurality of selection segments at overlapping spaced intervals, two of said second plurality of selective means being adapted at times to make different selections therefrom concurrently, said secondary preselector comprising a third plurality of selection segments and a third plurality of selective means each adapted to make similar selections from among said third plurality of selection segments at overlapping spaced intervals, two of said third plurality of selective means being adapted at times to make different selections therefrom concurrently, said third selector assembly comprising two primary preselectors, the first of said primary preselectors comprising a fourth plurality of selection segments and selective means adapted to select at least one of said fourth plurality of selection segments, the second of said primary preselectors comprising a fifth plurality of selection segments and selective means adapted to select simultaneously with said selection by said primary preselector at least one of said fifth plurality of selection segments being connected respectively to said third plurality of selective means, said fourth plurality of selection segments being connected respectively to said second plurality of selective means, said third plurality of selection segments being connected respectively to said first plurality of selective means, said coupling means correlating the selections of said first, second and third selector assemblies so that at a time when each of said primary preselectors is transferring from one to another of said fourth and fifth pluralities of selection segments respectively, the said two each of said first, second and third selective means are all selecting different ones of said first, second and third pluralities of selection segments respectively, whereby simultaneous progression of selections of said first selector assembly and of said selector of said second selector assembly is assured by the selective actions of said primary and secondary preselectors.

3. The switch as defined in claim 2 wherein said first primary preselector comprises a fourth plurality of selective means each adapted to make similar selections from among said fourth plurality of selection segments and at all times at least one of said fourth plurality of selection means making such selection, said second primary preselector comprises a fifth plurality of selective means each adapted to make similar selections from among said fifth plurality of selection segments and at all times at least one of said fifth plurality of selection means making such selection, said coupling means correlating the selections of said first, second and third selector assemblies so that in at least one continuous range of positions of said switch wherein the said two of each of said first, second, third plurality of selective means are continuously selecting different ones of said first, second, third plurality of selection segments, said fourth and fifth pluralities of selective means make one selection each from among said fourth and fifth pluralities of selection segments respectively at one segment of said continuous range of positions and a different selection each from among said fourth and fifth pluralities of selection segments respectively at another segment of said continuous range of positlons.

4. A sequential switch comprising a gear train, said gear train including a first shaft, a second shaft and a third shaft, means for driving said shafts in a 100 to 10 to 1 ratio, a first primary preselector, a second primary preselector, a units selector, said first and second primary preselectors and said units selector being carried on said first shaft, a secondary preselector, a tens selector, said secondary preselector and said tens selector being carried on said second shaft, a hundreds selector, said hundreds selector being carried on said third shaft, said primary preselectors, said secondary preselector, each having three slip rings and a three segment commutator, each segment of said three segment commutator coupled to one only of said slip rings, said units selector having a slip ring and a ten segment commutator, said tens and hundreds selectors each having three slip rings and a ten segment commutator, brush means for coupling the slip ring of said units selector to the segments of said units selector, means for delivering current to said slip ring of said units selector, means for delivering current to the commutator of said second primary preselector, brushes each fed from one slip ring only of said second primary preselector through a slip ring of said tens selector and engaging the commutator of said tens selector, means for delivering current to the commutator of said first primary preselector, and brushes each fed from one slip ring only of said hundreds selector through one slip ring only of said secondary preselector and one of a plurality of brushes for engaging the commutator of said secondary preselector coupled to one slip ring only of said first primary preselector for engaging the commutator of said hundreds selector.

5. A switch comprising a multiplicity of selector assemblies including a first assembly, a second assembly and a third assembly, coupling means connecting said selector assemblies for progression from one to another of their respective selections at different rates; said rates bearing a predetermined relationship to each other such that as the first of said selector assemblies progresses from one to another of its selections the second of said selector assemblies accomplishes a cycle of its selections and the third of said selector assemblies accomplishes a plurality of cycles of its selections, said first selector assembly comprising a first plurality of selection segments and a first plurality of selective means each adapted to make similar selections from among said first plurality of selection segments at overlapping spaced intervals, two of said first plurality of selective means being adapted at times to make different selections therefrom concurrently, said second selector assembly comprising a selector and a secondary preselector, said selector comprising a second plurality of selection segments, and a second plurality of selective means each adapted to make similar selections from among said second plurality of selection segments at overlapping spaced intervals, two of said second plurality of selective means being adapted at times to make dilferent selections therefrom concurrently, said secondary preselector comprising a third plurality of selection segments, and a third plurality of selective means each adapted to make similar selections from among said third plurality of selection segments at overlapping spaced intervals, two of said third plurality of selective means being adapted at times to make different selections therefrom concurrently, said third selector assembly comprising a selector and two primary preselectors, the first of said primary preselectors comprising a fourth plurality of selection segments and selective means adapted to select at least one of said fourth plurality of selection segments, the second of said primary preselectors comprising a fifth plurality of selection segments and selective means adapted to select simultaneously with said selection by said primary preselector at least one of said fifth plurality of selection segments being connected respectively to said third plurality of a selective means, said fourth plurality of selection segments being connected respectively to said second plurality of selective means, said third plurality of selection segments being connected respectively to said first plurality of selective means, said selector of said third selector assembly comprising a sixth plurality of selection segments and selective means adapted to successively select one of said segments of said sixth pluralityof selection segments, said coupling means correlating the selections of said first, second and third selector assemblies so that at a time when each of said primary preselectors is transferring from one to another of said fourth and fifth pluralities of selection segments respectively, the said two each of said first, second and third selective means are all selecting different ones of said first, second and third pluralities of selection segments respectively, whereby simultaneous progression of selections of said first selector assembly and of said selector of said second selector assembly is assured by the selective actions of said primary and secondary preselectors.

6. The switch as defined in claim 5 wherein said first primary preselector comprises a fourth plurality of selective means each adapted to make similar selections from among said fourth plurality of selection segments and at all times at least one of said fourth plurality of selection means making such selection, said second primary preselector comprises a fifth plurality of selective means each adapted to make similar selections from among said fifth plurality of selection segments and at all times at least one of said fifth plurality of selection means making such selection, said coupling means correlating the se lections of said first, second and third selector assemblies so that in at least one continuous range of positions of said switch wherein the said two of each of said first, second, third plurality of selective means are continuously selecting different ones of said first, second, third plurality of selection segments, said fourth and fifth pluralities of selective means make one selection each from among said fourth and fifth pluralities of selection segments respectively at one segment of said continuous range of positions and a different selection each from among said fourth and fifth pluralities of selection segments respectively at another segment of said continuous range of positions.

References Cited in the file of this patent UNITED STATES PATENTS Gulow May 8, 1951 2,666,912 Gow Ian. 19, 1954 

